In a small saucepan, simmer milk. Stir in saffron and butter and remove from heat. Allow to cool to lukewarm. In a mixer, blend flours, yeast, salt, sugar, and nutmeg. Add milk, eggs, and vanilla, and mix until well combined and dough is smooth. Place dough in a large oiled bowl. Set in a warm place for about one hour, until dough has almost doubled in size. Preheat oven to 375°F. Turn out dough on a lightly floured surface and divide into 12 pieces. Round each piece and allow to rest for about five minutes, then roll into 12-inch snakes. Let dough rest for five minutes, and then roll and twist each piece into a tight figure eight, tucking coiled ends under to hold the shape. Place on a parchment-lined pan at least three inches apart. Let dough rise again for 30 minutes, until almost double in size. Brush with egg white, sprinkle with sugar, and garnish with raisins or currants. Bake for 15 to 25 minutes until golden brown.